Valheim server does not appear in the server list

A Valheim server is listed only when Public Server is on and the server is Online with its world loaded. If it is not in the list, check those two first. You can always join by address or join code in the meantime.

Checks

1. Is it Online? The badge must say Online. A server that is still starting is not listed yet.
2. Is Public Server on? Click Settings, then Game Settings, and check Public Server. Off hides the server on purpose. See How to make your Valheim server public or private.
3. Did you restart after changing it? A change takes effect at the next start.
4. Is the server name short enough? Server Name can be up to 53 characters. With crossplay on, a longer name makes the server fail to log in, and it stops.
5. Is crossplay what you expect? With Enable Crossplay off, only Steam players can see and join the server. With it on, players on other platforms use the join code or the address. See How to turn crossplay on or off on your Valheim server.
6. Look for the right name. The list shows the name in Server Name in Game Settings, not the name at the top of the panel page.

Join without the list

• By address: copy it from the Play with friends card. See How to join your Valheim server from Steam.
• By join code, with crossplay on: How to find your Valheim join code.

Iron Gate's own guide says that a server that is not public is joined with the Join IP button, and that a crossplay server can be reached by address, join code or the server list.

Still not there?

If you can join by address but the server never appears, open a ticket with your server name and what you see in the list.